The answer is that you need to get a new eSim. I tried all of the other troubleshooting that is suggested on the web and that didn’t work for me.
Now getting a new eSim is not the preferred solution by your mobile phone company. I spent most of today wasting time doing things that didn’t work, in addition to the time I spent troubleshooting it myself.
The mobile company will try to get you to waste your time doing that junk, but just tell them you want this and then get on with your life. I spent 4 hours today fixing two iphones that had exactly the same issue. What a process that was, and I am just working on another article about how much that process lacked.
Now if you don’t care that your messages are green and unencrypted then ignore my advice. I have faced this problem with the last 3 iPhone OS upgrades. Annoying that Apple hasn’t fixed it yet. I hate it when companies don’t care about their user experiences. Hey Apple, the glass interface isn’t cool. Fixing old problems is cool.